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I've been thinking a bit about this stuff, the problem is hard - as the premise is messy to begin with (Jamma). For controls, and possibly audio/video one option is to use network cables - they come in any length and color you could think of - and some of them can be quite flexible too. RJ45 PCB connectors are also easily sourced. Downside is you will need a few of them..
 
I got a start on the PCB. There will be two separate PCBs, one with a jamma finger and the other with a jamma edge connector. Both will have female 24 pin ATX and 34 pin IDC connectors which will allow them to be connected via a 24 pin ATX extension cable and 34 pin IDC ribbon cable.

JAMMA-EXTENDER.png
I don't know if your first idea iwasn't actually better to have large wire gauge only for power, there should be no harm to put audio and video on SHORT IDC cable and just to give a smaller connector to power with extra gauge.

When I think about IDC, these ribbon cables are hell to handle when they need to make anything that is not straight in front of the PCB. I think they are ideal to make a PATCH extender to avoid damage, but not that good to handle inside a cabinet. I wouldn't go more than 15cm for those because of two reasons, wire gauge and manipulation.

I see two roads :

30cm extender : more manipulable cable than ribbon cable inside a cab, it could be 2xATX or a hub of RJ45 like suggested @invzim it's a great idea
15cm : ribbon cable and small power connector just to serve the connector fragility issue
 
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I've been thinking a bit about this stuff, the problem is hard - as the premise is messy to begin with (Jamma). For controls, and possibly audio/video one option is to use network cables - they come in any length and color you could think of - and some of them can be quite flexible too. RJ45 PCB connectors are also easily sourced. Downside is you will need a few of them..
For controls and buttons I agree, for video and audio I think they are a tad on the thin side.
 
@'Sp33dFr34k it depends on distance, my monitor has a long vga cable but on the chassis side it's just a small jst patch cable.
 
A lot of people run VGA over cat5 rj45 as they work better for longer distances than normal VGA, so I think that should be OK. With RJ45, you could use the same system to tidy up/replace cabinet wiring, e.g
1 - Player 1 joystick
2 - Player 2 joystick
3 - Player 1 Buttons
4 - Player 2 Buttons
5 - Coins etc
6 - Video

Problem is of course, you end up with a bunch of RJ45 that is probably as messy as jamma to begin with, but it could be cool with tiny breakout boards where the signals are actually needed. As I said, I think the problem is 'hard', and there may not be a fantastic solution for this.
 
Maybe you should consider voltmeter in your design, consdering how cheap they are and how useful it is to have it on ? Pointless for use with a HAS or something that already have one, but probably useful for cab use
 
Well I've finished the jamma finger board. The jamma edge board is basically the same but with a slightly different edge to accommodate soldering on a jamma edge connector and connections reversed to match.
JAMMA_EXTENSION.png
 
good job, I still think ATX 24 pins is overkill, maybe you can reduce to 20 pins connector.

I would also give a chance to a smaller footprint design lwith only IDC 50 + Molex and test the results, I bet they would work the same for short range
 
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Well using 24p ATX I had 1 pin free so I used it as extra ground point. I've used a large ground plane so no troubles there and ample pins for the other power rails with 50mil traces.

Problem with 20 pin is pre-made harnesses aren't as common and I'm happy utilising all power, video and audio over the better quality wiring an ATX cable contains.

I'm not adding anything extra like voltmeter etc, just keeping it simple and functional.

The PCB is 38mm high so quite compact and there's two 3mm holes for feet.

It should work well.

I'm not looking at profiting from this and will happily release the files for people to order their own. Compoment count is quite small, 2 x angled 24 pin ATX connectors, 2 x angled 34 pin IDC connectors, 1 x jamma edge and then the wire harnesses which can be purchased pre-assembled.
 
ok I didn't realize there was only one pin left... last thought is for IDC, are they easy to find as non flat ribbon ?
 
Well you could fabricate your own cable, but you'll need 31 core cable.
 
I often have funny angles to deal with inside my cabinet, some cables like the flat ribbon can do some cool things but can be pretty annoying when turning in a 90 degrees, wellI will think about that later yes, it shouldn't be that hard, the most important is done now congrats for your design
 
This is primarily more designed for a supergun rather than cab.

As has been mentioned, there's no real ideal solution, it's a tough one. Just so many wires and requirements.
 
I have no doubt it would work on a cab too with the jammafier.

The only doubt I still have is this ATX 24pins, this bugger is pain in the ass because it puts a lot of strain on solders when things move. The cable has a lot of resistance / wieght that can press/lift the pcb on both sides.

This thing is designed to move often si it has to be durable and avoid accidental solder breaking.

I still don't believe at 100% for 30cm we need this bulky connector except for power.

The less you can have to deal with thick cable connectors the more durable the design can be.

Only tests can prove anyway.
 
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I agree that 24-pin ATX isn't much better than a regular JAMMA harness in the grand scheme of things when it comes to mechanical issues. I also agree that RJ45 and CAT5e is the way to go for video as it has the bandwidth and cabling is everywhere, plus you have 4x twisted pairs, so each component of RGBS can have it's own dedicated twisted pair and matching ground that goes to the dedicated video ground pin.

I don't think JAMMA ever officially specified anything more than a single speaker at 5W with 8 ohms impedance, right? if so, ohms law says we should be roughly in-spec for 28 AWG IDC on a short run? Putting the speaker wires on the IDC 34 cable should nicely use all 34 available pins.

Power-wise, have you looked into the 8-pin TE MTA-156? It's rated for enough current (orange connector) and should be the easiest thing ever to make cables for with an 18 AWG IDC cable and a punch down tool. There's JST VR as well, but seems rare?

What's the official JAMMA spec for current across +5, +12, and -5 anyways?
 
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I have a JAMMA extension cable with 2 female endings and I just use a cut off fingerplate to turn one to male. Got it a long time ago from Mikes Arcade or something I believe.
I'm still looking for a descent one with all pins connected though.
 
I'm not sure what the standard specifies re power but I always allow 15 Amps for the +5V line. +12V I don't think exceeds 1 Amp so catering for 2 Amp should be safe, -5V is typically 0.5 to 1 Amp.
 
I only have one board that utilises -5V and it pulls just under 0.5A. Every arcade PSU I've seen never goes higher than 1 Amp rating on the -5V rail so I doubt any board is pulling more than that, especially when all it's used for is powering a tiny OP amp.
 
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